McMaster-Carr logo
    Filter by
    Body Diameter
    DFARS Specialty Metals
    Export Control Classification Number (ECCN)
    Industrial Info Snippet
    U.S.–Mexico–Canada Agreement (USMCA) Qualifying
    Forward
    Enter e-mail addresses in the fields below
    Message
    Cancel
    Print
    How can we improve?
    Comments
    E-mail address (if you would like a response)
    14 Products
    About Counterbores
    industrial info icon

    Create flat-bottomed holes, so your screw heads sit flush, recessed, or slightly raised.

    Reverse Counterbores

    If the hole is obstructed, these counterbores drill from the reverse side instead. They're handy for adding counterbores to existing installations.
    After drilling your through hole, put the shank (sold separately) in your drill chuck and insert it all the way through. Then reach into the confined space to stick the counterbore head onto the shank. Pull back on the drill to counterbore the hole.
    High-Speed Steel
    Image of ProductInUse. Front orientation. Contains Annotated, Border. Counterbores. Reverse Counterbores.
    Image of Product. Counterbore Head. Front orientation. Contains Annotated. Counterbores. Reverse Counterbores.

    Counterbore Head

    Durable and wear resistant, these counterbores make accurate cuts in most materials without chipping or cracking.
    Counterbores
    Required Shanks
    Uncoated
    Body
    Dia.
    Overall
    Lg.
    No. of
    Flutes
    Each
    Shank
    Dia.
    Overall
    Lg.
    Each
    5/16"1/2"43323A210000003/32"6"3309A3100000
    5/16"1/2"43323A22000001/8"6"3309A320000
    5/16"1/2"43323A23000005/32"6"3309A330000
    3/8"1/2"43323A24000001/8"6"3309A320000
    3/8"1/2"43323A25000005/32"6"3309A330000
    3/8"1/2"43323A26000003/16"6"3309A3400000
    1/2"1/2"43323A27000005/32"6"3309A330000
    1/2"1/2"43323A28000003/16"6"3309A3400000
    1/2"1/2"43323A29000001/4"6"3309A3500000
     
    back to top